Tutorials

If you are starting out with Yambo, or even an experienced user, we recommend that you complete the following tutorials before trying to use Yambo for your system.

The tutorials are meant to give some introductory background to the key concepts behind Yambo. Practical topics such as convergence are also discussed. Nonetheless, users are invited to first read and study the background material in order to get familiar with the fundamental physical quantities.

Two kinds of tutorials are provided: stand-alone and modular.

The tutorial CORE databases can be downloaded one by one via the link provided below or by using the yambo GIT tutorial repository.

Tutorial Repository

This repository contains the updated tutorials CORE databases. To use it

$ git clone git@github.com:yambo-code/tutorials.git YAMBO_TUTORIALS
$ cd YAMBO_TUTORIALS
$ ./setup.pl -install

Tutorial files

All tutorials require download of pre-prepared Yambo databases or DFT input files. After downloading the tar.gz files just unpack them in the YAMBO_TUTORIALS folder. For example

$ mkdir YAMBO_TUTORIALS
$ mv hBN.tar.gz YAMBO_TUTORIALS
$ cd YAMBO_TUTORIALS
$ gunzip hBN.tar.gz
$ tar -xvf hBN.tar
$ ls
  YAMBO_TUTORIALS
$ ls YAMBO_TUTORIALS
  hBN

Files needed for modular tutorials

All of the following should be downloaded prior to following the modular tutorials:
hBN.tar.gz hBN-2D.tar.gz hBN-2D-para.tar.gz

Files needed for stand-alone tutorials

At the start of each tutorial you will be told which specific file needs to be downloaded:
Silicon.tar.gz LiF.tar.gz Aluminum.tar.gz Hydrogen_Chain.tar.gz

Stand-alone tutorials

These tutorials are self-contained and cover a variety of mixed topics, both physical and methodological. They are designed to be followed from start to finish in one page and do not require previous knowledge of yambo. Each tutorial requires download of a specific core database, and typically they cover a specific physical system (like bulk GaSb or a hydrogen chain). Ground state input files and pseudopotentials are provided. Output files are also provided for reference.

These tutorials can be accessed directly from this page of from the side bar. They include different kind of subjects:

Basic

• Linear Response in 3D. Excitons at work
• GW convergence

Advanced

• TDDFT Failure and long range correlations
• Real Axis and Lifetimes
• Linear response from real time simulations
• Real time approach to non-linear response
• Correlation effects in the non-linear response

Modular tutorials

These tutorials are designed to provide a deeper understanding of specific yambo tasks and runlevels. They are designed to avoid repetition of common procedures and physical concepts. As such, they make use of the same physical systems: bulk hexagonal boron nitride hBN and a hBN sheet hBN-2D. Files for both systems must be downloaded, and make sure to extract the tarballs in the same place.

Download: hBN.tar.gz hBN-2D.tar.gz hBN-2D-para.tar.gz

Introduction

• First steps: a walk through from DFT to optical properties

Quasiparticles in the GW approximation

• How to obtain the quasi-particle band structure of a bulk material: h-BN

Using Yambo in Parallel

This modules contains very general discussions of the parallel environment of Yambo. Still the actual run of the code is specific to the CECAM cluster. If you want to run these modules just replace the parallel queue instructions with simple MPI commands.

• Parallel GW (CECAM specific): strategies for running Yambo in parallel

GW_parallel_strategies_CECAM

• GW convergence (CECAM specific): use Yambo in parallel to converge a GW calculation for a layer of hBN (hBN-2D)

Excitons and the Bethe-Salpeter Equation

• Calculating optical spectra including excitonic effects: a step-by-step guide
• Obtaining a converged optical spectrum
• Many-body effects in low-dimensional systems: numerical issues and remedies
• Analysis of excitonic spectra in a 2D material

Yambo-python driver

• First steps in Yambopy
• GW tutorial. Convergence and approximations (BN)
• Bethe-Salpeter equation tutorial. Optical absorption (BN)

Modules

Alternatively, users can learn more about a specific runlevel or task by looking at the individual documentation modules. These provide a focus on the input parameters, run time behaviour, and underlying physics. Although they can be followed separately, non-experts are urged to follow them as part of the more structured tutorials given above.